Four-frequency radiowave propagation measurements of the indoor environment in a large metropolitan commercial building

Time delay spread and signal level measurements were made in a large commercial metropolitan building at 850 MHz, 1.9 GHz, 4.0 GHz, and 5.8 GHz. No significant statistical difference in time delay spread was found at the four frequencies. The maximum RMS time delay spread at the four frequencies did not exceed 120 ns. Attenuation was very nearly the same at the four frequencies, within the limits of the experiment´s accuracy. The variation of the received signal level with distance could be characterized by free space propagation together with attenuation per unit distance. This attenuation coefficient was about the same at the four frequencies. The RMS fractional deviation was found to be a useful measure of the spread of the data